Advanced Materials Research Vols. 217-218

Abstract: In the information era, information security becomes more important, the use of EEG as identification tool become more and more. In this paper, we used the subjects’ photos as stimulation. In order to obtain the Identification classifier of different subjects, we used AR model to convert the EEG signals from time domain into the frequency domain, used Fisher’ distance to extract the feature. Finally, we calculated the feature by using BP neural network. Through the analysis of the correct recognition rate, error recognition rate and false recognition rate, we achieved the purpose of using EEG as identification tool.

Abstract: The powder injection molding (PIM) combines the thermoplastic and powder metallurgy technologies to manufacture intricate parts to nearly shape. The powder segregation is a special effect arising in PIM different from than the pure polymer injection. The two-fluid flow model is used to describe the flows of binder and powder so as to realize the prediction of powder segregation effect in PIM injection. To take into account binder–powder interaction, the mixture model of inter-phase exchange term is introduced in the two-fluid model. The two-fluid equations largely resemble those for single-fluid flow but are represented in terms of the mixture density and velocity. The volume fraction for each dispersed phase is solved from a phase continuity equation. As the key to calculate the phase exchange term, the drag coefficient is defined as a function of mixture viscosity. The effective viscosity of binder and powder are agreed with the additive principle. The volume fractions of binder and powder give directly the evolution of segregation during the injection course. Segregation during PIM injection was simulated by software CFX and results were compared with experimental data with good agreement. The basic reasons that caused segregation are identified as boundary effect, differences in density and viscosity of binder and powder. The segregation zones are well predicted. This showed that the two-fluid model is valid and efficient for the prediction of the segregation effects in PIM injection.

Abstract: Through the experiment on the durability of sea sand concrete beam which is subject to climate conditions and indoor environment, the change of deflection, beam load-deflection curve, ductility and crack are studied. The results show: concrete beams that are mixed with sea sand are deteriorated by the chloride ion and their load-deflection curves as well as stiffness and ductility are reduced in different degree. But other beams that are mixed with desalinated sea sand are reduced not obviously. Otherwise, because of the bad environment accelerating degradation of the component mechanical performance and the sea sand desalination technology increasing the ability to resist environmental erosion, the component mechanical performance and the sea sand desalination technology take great influence to the component mechanical performance.

Abstract: Through the experiment on HPC beam which is subject to artificial climate conditions and indoor natural environment, section strain, beam load-deflection curve, failure and cracks are studied. The results show: compared with ordinary concrete beam, the HPC beam which has been subject to artificial climate conditions has higher stiffness; the deflection amount and the width of crack of this concrete beam all fall in the confines of ultimate service state under use load; and the beam displays a better ductility in failure

Abstract: The resonance properties of surface plasmon in the IMM/dielectric/IMM waveguide are theoretically studied by using finite-difference time-domain technique, where the claddings are indefinite metamaterials (IMMs). From the dispersion relation, it is found that the IMM/dielectric/IMM waveguide supports TE polarized surface plasmon if IMM is always-cutoff with negative permeability. For an IMM/dielectric/IMM waveguide with a finite length, a subwavelength plasmon microcavity can be formed by Fabry-Perot resonance. At the resonant frequency, the magnetic field is maximized at the dielectric core entrance and exit, the electromagnetic energy is strongly concentrated around the dielectric core. When an artificial magnetic resonator is put at the core entrance and the resonance frequency is tuned to the plasmon microcavity mode, Rabi splitting can appear because of the strong coupling between this resonator and the cavity mode.

Abstract: . In order to implement the accuracy and robust classification of Chinese dates according to size and shape based on machine vision techniques on line, the method of classification according to size and shape for Chinese dates was studied. The Chinese date is segmented from the background in RGB color space by analyzing respectively the histogram of R, G and B channel to make comparing among them and find an optimal one, resulting in good contrast between Chinese date and background in G channel. Three different profile image of a Chinese date were gained to calculate the diameter of the Chinese date and the maximum diameter value was used to be the character value for size classification. The ratio of maximum radius and the minimum radius was used to be the character value for shape classification. Experiment results proved the methods is effective to classify Chinese date by size and shape.

Abstract: Based on knowledge equivalent classification of an uncertain system, from view of the knowledge coordinating relations and dependence of condition attributes and the decision attributes in an information universe，a new concept of information consistency of a database is presented to simplify knowledge of an uncertain system. A basic algorithm and realization of knowledge simplification on the information consistency of a database is suggested in this paper. It is more legible and convenient for knowledge simplification by way of the information consistency of a database than the idea of knowledge dependence. The feasibility of the proposed approaches of knowledge simplification and reasoning decision rules is validated by some of example of a classic CTR car knowledge representation system with a large-scale database here.

Abstract: Fatigue failure of steel occurs when cracks form in a component and continue to grow to a size large enough to cause fracture. In order to understand the strength of a steel component, it is important to locate these cracks. We developed a scanning Hall probe microscope (SHPM) equipped with GaAs films sensors and observed fatigue cracks at room temperature in air while they were growing. In our previous works, we determined the correlation between crack growth and magnetic field in high carbon tool steels (JIS SKS93 and JIS SUJ2). We also reported the sensitivity of the SHPM equipped with a three-dimensional line-probe that was developed to decrease the sensor gaps. By using the line-probe sensor we succeeded to measure the magnetic flux density distributions in very close proximity to the specimen’s surface. However, in order to further understand the relation between magnetic flux density and crack growth, other materials, microstructures and fatigue test conditions should be evaluated. In the present work, we focus on the effect of stress ratios on the changes of the magnetic flux density in annealed carbon tool steel.

Abstract: For a continuum structure filled with many solid phases with different stiffness, the layout of the materials should be optimized to perform an excellent structural mechanical behaviour. The differences between the materials’ moduli affect the final layout of materials in structure. To investigate the effects, a numerical approach is adopted to find the optimal topology of a continuum with multiple materials. In the method, the layout of the material is determined by the local strain energy density (SED). Briefly, in design domain, a material point with higher SED should have higher modulus. To show the effects obviously, a continuum with three phases is used for experiment. In the structure, the modulus of the stiffest material and the volumes of materials are fixed. The other materials’ moduli change alternately. Numerical results demonstrate the layout of materials in structure depends on the differences between the moduli greatly, and the topology of the stiffest material is clear if its modulus is far more than the others.

Abstract: In this paper, an embedded elliptical crack in a weld of pressure vessels under tension was taken into consideration, and stress intensity factors at the crack tip were calculated numerically with the emphasis on the influences of the weld surface. It is found that when the embedded depth is 4 times larger than the minor semi-axis of the ellipse, the weld surface effects on the crack can be neglected and the numerical solutions for the stress intensity factors well agree with the analytical ones. This result can be used to distinguish a shallow embedded crack from a deep embedded crack. It is also found that the point with maximum stress intensity factor is always located at the end of minor axis of the ellipse no mater the shape of the ellipse is and how deep it was embedded.